What should be Total Fertility Rate (TFR) of a population in order to reach at the replacement level of fertility?

Question

UnlockIAS · Accepted Answer

Correct — C, 2.1. The Total Fertility Rate (TFR) is the average number of children a woman would bear over her reproductive years (15–49) at current age-specific fertility rates. 'Replacement level' is the TFR at which each generation exactly replaces itself. Logically it needs to be a little above 2.0: a woman must be replaced by one daughter and her partner by one son (≈2 children), plus a small margin for girls who die before reaching child-bearing age and for the fact that slightly more boys than girls are born. That margin makes the standard replacement-level TFR ≈ 2.1 in countries with low mortality — which is why (c) is the accepted answer.

Why the other options are wrong — (a) Wrong — a TFR of 1.0 is far below replacement; a population with about one child per woman would shrink rapidly each generation.  (b) Wrong — 1.6 is a 'below-replacement' rate typical of ageing low-fertility societies; it does not replace the parent generation.  (d) Wrong — 2.3 is above replacement (mild growth). Replacement level is pegged at about 2.1, not 2.3, in low-mortality populations; 2.3 is a distractor set just above the correct value.

Concept: Total Fertility Rate (TFR) is the average number of live births a woman would have by the end of her child-bearing years if she experienced the prevailing age-specific fertility rates. Replacement-level fertility is the TFR that keeps a population's size constant across generations (ignoring migration). Because a couple must produce roughly two surviving children and a small allowance is needed for pre-reproductive mortality and the slight excess of male births, the replacement TFR is about 2.1, not exactly 2.0.

State PCS 2020 Q117 — Geography PYQ with Answer

State PCS 2020 Q117 — Geography PYQ with Answer